| タイトル | The Low Energy Effective Area of the Chandra Low Energy Transmission Grating Spectrograph |
| 著者（英） | Kashya, V.; Pease, D.; Paerels, F. B.; Brinkman, A. C.; Ratzlaff, P. W.; Johnson, C. O.; Kaastra, J. S.; vanderMeer, R.; Wargelin, B. J.; Drake, J. J. |
| 著者所属（英） | Smithsonian Astrophysical Observatory |
| 発行日 | 2000-01-01 |
| 言語 | eng |
| 内容記述 | The Chandra X-ray Observatory was successfully launched on July 23, 1999, and subsequently began an intensive calibration phase. We present the preliminary results from the in-flight calibration of the low energy response of the High Resolution Camera spectroscopic readout (HRC-S) combined with the Low Energy Transmission Grating (LETG) aboard Chandra. These instruments comprise the Low Energy Transmission Grating Spectrograph (LETGS). For this calibration study, we employ a pure hydrogen non-LTE white dwarf emission model (T = 25000 K and log g = 9.0) for comparison with the Chandra observations of Sirius B. The pre-flight calibration of the LETGS effective area only covered wavelengths shortward of 44 A (E less than 277 eV). Our Sirius B analysis shows that the HRC-S quantum efficiency (QE) model assumed for longer wavelengths leads to an overestimate of the effective area by an average factor of about 1.6. We derive a correction to the low energy HRC-S QE model to match the predicted and observed Sirius B spectra over the wavelength range of 44-185 A. We make an independent test of our results by the comparison of a Chandra LETGS observation of HZ 43 with pure hydrogen model atmosphere predictions and find good agreement. |
| NASA分類 | Astronomy |
| 権利 | No Copyright |
|
